Increase In Nanofluid Concentration Research Articles

Improving hydrothermal performance of a tubular heat exchanger with different types of twisted tapes using graphene nanoplatelets/water nanofluid

ABSTRACT A comparative experimental investigation in order to evaluate the hydrothermal characteristics of a heat exchanger tube fitted with varied types of twisted tape is performed using graphene nanoplatelets (GNP) and water nanofluid. The experiment is carried out for three varied weight concentrations (ω = 0.05%, 0.075% and 0.1%) of GNP/water nanofluids flowing in a tube fitted with various twisted tapes of three different twist ratios (x/b = 3, 4 and 5) for the Reynolds number of 6700 –33,200 and a nanofluid flow rate of 5 to 25 lpm. The results showed the heat transfer rate and pressure loss increased with rising Reynolds numbers, a decrease in the twist ratio of tapes, and an increase in nanofluid concentration. The specially designed anti-clockwise clockwise twisted tape (ACCT) insert provides a 67.8% greater heat transfer coefficient than typical twisted tape. The addition of GNP nanoparticles to water has a significant impact on the increase in heat transfer rate. The best hydrothermal performance factors achieved are 2.03, 1.93, and 1.84 for ACCT tape (x/b = 3) fitted tube at Reynolds number of 26,600 for 0.1%, 0.075%, and 0.05% weight concentration of GNP/water nanofluids, respectively. Nusselt number and friction factor correlations are also established in terms of twist ratio, Reynolds number, and nanofluid concentration parameters.

Experimental Study on the Effect of TiO2–Water Nanofluid on Heat Transfer and Pressure Drop in Heat Exchanger with Varying Helical Coil Diameter

The growing demand for efficient heat exchangers has promoted extensive research in exploring advanced heat transfer fluids and novel geometries. This paper investigates the heat transfer and pressure drop characteristics in helical coil heat exchanger employing water-based TiO2 as nanofluid. The utilization of nanofluids offers promising enhancements in thermal conductivity and convective heat transfer in heat exchanger applications. The effect of nanofluid concentration and flow rate on heat transfer and pressure drop with varying helical coil diameter performance is investigated. Experimental tests were conducted using a heat exchanger with different helical coil pipe diameters of 9.53mm, 12.7mm and 15.88mm with constant pitch of 30mm and varying concentrations of TiO2 nanoparticles in water (ranging from 0.1% to 0.5% by volume). The heat transfer coefficient and pressure drop were measured at different operating conditions. The results shows that the addition of TiO2 nanoparticles to water significantly enhanced the heat transfer performance in the helical coil heat exchanger. There is an enhancement in heat transfer coefficient with increasing nanofluid concentration and with increase in pipe diameter. The maximum enhancement in heat transfer coefficient is observed at nanofluid concentration of 0.5% and for pipe diameter of 15.88 mm. However, there is increase in pressure drop with increase in nanofluid concentration and with decreasing pipe diameter. The pressure drop found to be higher for nanofluids compared to pure water. The maximum pressure drop is observed at a concentration of 0.5% and for pipe diameter 9.53mm. In conclusion, the use of a water-based TiO2 nanofluid in a helical coil heat exchanger offers improved heat transfer performance compared to pure water. However, the pressure drop also increases with nanofluid concentration and decreasing pipe diameter. Therefore, a trade-off between heat transfer enhancement and pressure drop should be considered in the design and operation of such heat exchangers.

Numerical modeling of magnetic field impact on the thermal behavior of a microchannel heat sink

The current appraisal evaluates the heat transfer phenomena of the nanofluid stream through the microchannel heat sink, considering the existence of a magnetic field. Moreover, Aluminum oxide (Al2o3)-water nanofluid is elected and implemented as a cooling fluid in this study. Also, the Koo–Kleinstreuer model (KKL correlation) is provided for the computation of the viscosity and effectual thermal conductivity of the nanofluid. Improved Darcy relationship is used for modeling the porous medium, and the two-equation approach's dispersion type is utilized for poking the heat transfer phenomenon among the solid and fluid zones. Due to the nonlinearity of the linked heat transfer relationships in mentioned phases, the well-known analytical Collocation method (CM) model decodes the issue. The influence of the void fraction and the diameter of the nanoparticles, temperature distribution, Hartmann number, fluid velocity, and channel geometry are discussed comprehensively. The obtained outcomes indicate that implementing the magnetic field has a direct connection with the Nusselt number. It was also found that heat transfer increases with the increase in nanofluid concentration. So, for the concentration of 0.04, there is the highest amount of heat transfer.

A unique artificial intelligence approach and mathematical model to accurately evaluate viscosity and density of several nanofluids from experimental data

In the present research paper, a unique single feed-forward multilayer perceptron neural network (MLPNN) based on data transformation technique and mathematical models were proposed for forecasting density and dynamic viscosity of Alumina (Al2O3)/distilled water (DW), multiwall carbon nanotube (MWCNT)/DW, and Graphene nanoparticle (GNP)/DW nanofluids. The density and dynamic viscosity of nanofluids (0.1%, 0.25%, 0.5%, 0.75%, and 1%) were experimentally measured in temperature range 30–80 °C. Nanofluids, volume concentration, and temperature were given as input and density and dynamic viscosity as output from the network. The statistical analysis was performed to predict the accuracy of both models. The experiments revealed that density and viscosity increase with an increase in nanofluid concentration, and decrease with an increase in temperature. The maximum increase in dynamic viscosity and density of 41.59% and 5.06% was noticed for Al2O3/DW nanofluid. The outcome shows that the MLPNN model is well trained at 12 perceptrons in the hidden layer using the Levenberg-Marquardt algorithm. The output obtained from MLPNN and the mathematical model were compared with experimental results. The maximum error < 0.2% in density and < 1% in viscosity measurement was noticed for both models.

Heat transfer characteristics and entropy generation analysis in a plate heat exchanger using ethylene glycol and water mixture‐based Al2O3nanofluid

AbstractThe present study aims to study the heat transfer and entropy generation analysis in a plate heat exchanger by dispersing Al2O3nanoparticles into a water and ethylene glycol mixture (base fluid) of a 65:35 volume ratio. The study was carried out by varying the nanofluid concentration from 0.2 to 2 wt%. The effects of Peclet number and weight concentration of water:ethylene glycol–Al2O3nanofluid on heat transfer characteristics and entropy generation were investigated. The nanofluid and distilled water were considered as a cold medium and hot medium on the plate heat exchanger, respectively, for the experimental study. The study showed considerable improvement in convective heat transfer coefficient and Nusselt number with the increase in nanofluid concentration. The study showed a 19.32% enhancement in overall heat transfer coefficient compared with base fluid at identical Peclet number. Pressure drop and pumping power were increased due to the addition of nanoparticles. Improved effectiveness was observed with the increase in concentration at higher Peclet numbers. Thermal entropy generation and friction entropy generation showed descending and ascending trends, respectively, for the considered weight concentration of nanofluid for the increased Peclet number. The Bejan number and entropy generation number demonstrated the roles of heat and friction in the entropy generation. A correlation was developed to predict the Nusselt number considering the experimental data. The prediction of the Nusselt number obtained from the present study showed good agreement with the experimental results.

Evaluation of Multiple Semi-Twisted Tape Inserts in a Heat Exchanger Pipe Using Al2O3 Nanofluid.

The hydrothermal performance of multiple semi-twisted tape inserts inside a heat exchanger pipe is numerically examined in three-dimensions. This study aims to find the optimum case for having the highest heat transfer enhancement with the lowest friction factor using nanofluid (Al2O3/water). A performance evaluation criterion (PEC) is defined to characterize the performance based on both friction factor and heat transfer. It was found that increasing the number of semi-twisted tapes increases the number of swirl flow streams and leads to an enhancement in the local Nusselt number as well as the friction factor. The average Nusselt number increases from 15.13 to 28.42 and the average friction factor enhances from 0.022 to 0.052 by increasing the number of the semi-twisted tapes from 0 to 4 for the Reynolds number of 1000 for the base fluid. By using four semi-twisted tapes, the average Nusselt number increases from 12.5 to 28.5, while the friction factor reduces from 0.155 to 0.052 when the Reynolds number increases from 250 to 1000 for the base fluid. For the Reynolds number of 1000, the increase in nanofluid concentration from 0 to 3% improves the average Nusselt number and friction factor by 6.41% and 2.29%, respectively. The highest PEC is equal to 1.66 and belongs to the Reynolds number of 750 using four semi-twisted tape inserts with 3% nanoparticles. This work offers instructions to model an advanced design of twisted tape integrated with tubes using multiple semi-twisted tapes, which helps to provide a higher amount of energy demand for solar applications.

Energy, exergy and economic analysis of liquid flat-plate solar collector using green covalent functionalized graphene nanoplatelets

• Thermal efficiency of solar collector increased using eco-friendly nanofluids with maximum improvement up to 24%. • Exergy efficiency increased with weight concentration of eco-friendly nanoparticles. • Maximum increase in friction factor was around 7.9% for 0.1% nanofluid than base fluid. • Relative pumping power slightly increases with increment in nanofluid concentration but is quite close to that of the base fluid. • Pay back period was 5.615% lesser using nanofluids than water. The conventional method of synthesizing carbon-based nanofluids produces harmful products that are highly toxic and hazardous. The present investigation deals with the effects of using eco-friendly, non-corrosive, covalent functionalized Graphene Nanoplatelets with gallic acid (GGNPs) as heat transfer fluid on energetic and exergetic performance of a Liquid flat-plate solar collector (LFPSC). Long-term dispersible stable GGNP nanofluids with base fluid distilled water are prepared with different weight concentrations of 0.025%, 0.05% & 0.1%. For varying concentrations, fluid flow rates of 0.8, 1.2, and 1.5 L/min, heat flux intensities of 600, 800, and 1000 W/m 2 , and inlet temperature ranging from 303 to 323 K are considered for the conduction of experiments. Improvement in energy and exergetic efficiency was achieved using GGNP nanofluids. Thermal efficiency surges with increment in flow rate and heat flux intensities, meanwhile it decreases for increment in inlet temperature. The maximum enhancement in LFPSC efficiency is 24.09% for 0.1 wt% GGNPs and flow rate of 1.5 L/min than distilled water. Analysis of exergetic performance revealed that exergy efficiency reduces with a rise in mass flow rate meanwhile enhanced with an increase in nanofluid concentration. Exergy efficiency was maximum for 0.1% GGNP concentration and flow rate of 0.8 L/min. The maximum increase in friction factor values is approximately 1.5, 2.6 and 7.9% for 0.025, 0.05 and 0.1% GGNP nanofluids than distilled water. Relative pumping power slightly increases with the increment of GGNP concentration but is quite close to that of the base fluid. Performance index greater than one is obtained with higher values achieved at an increase in GGNP weight concentration. Economic consideration of GGNP nanofluids in LFPSC showcased a maximum reduction of 26.41% in the size of collector area using 0.1% GGNP nanofluid instead of distilled water. The payback period for LFPSC using GGNPs was 5.615% lesser than that of using water.

Energy and exergy analysis of a ground source heat pump system with a slinky ground heat exchanger supported by nanofluid

This work contains the experimental analysis results in real environment conditions of the use of $$\hbox{Al}_2\hbox{O}_3$$ -based nanofluid (NF) at different concentration ratios (0.1% and 0.2%) in a ground source heat pump (GSHP) system with a slinky ground heat exchanger (GHE). The energetic and exergic efficiencies of the system were investigated with the data obtained from the experimental results of base fluid (ethylene glycol (EG)-water) (EG volumetric ratio 25%) and NF with $$\hbox{Al}_2\hbox{O}_3$$ concentration ratios of 0.1% and 0.2%. The exergetic model is obtained by applying energy and exergy equations for each system component. Exergetic efficiencies of the system components are evaluated separately and their potential for improvement is presented. According to the results of the energetic analysis, the overall system’s coefficient of performance (COP) values for the base fluid and NF with concentration ratios of 0.1% and 0.2% were 4.30, 4.38 and 4.34, respectively. These results show that NF contributes to system performance. However, an increase in system performance was not achieved due to the increase in NF concentration; on the contrary, a decrease in performance was observed. Exergetic efficiencies of the system for base fluid and NF with concentration ratios of 0.1% and 0.2% were 88.3%, 89.7% and 89.0%, respectively, for the heat pump unit, while these values were 78.7%, 79.3% and 79.0% for the entire system, respectively. The results show that the usage of NF with low concentration ratios increases the energetic and exergic efficiency of the system.

Improvement of CO2 absorption by Fe3O4/water nanofluid falling liquid film in presence of the magnetic field

AbstractCarbon dioxide is considered as the main greenhouse gas responsible for climate change. Absorption of CO2 by liquid phase has gained attention as a means of mitigating environmental challenges. In this study, the effect of Fe3O4 nanoparticles on the CO2‐water mass transfer coefficient was experimentally evaluated in the presence and absence of a magnetic field. The absorption experiments were carried out in a falling liquid film absorber system in laminar and turbulent flow regimes. Fe3O4/water nanofluid was used in 0.001‐0.05 vol% concentrations. The results show that adding Fe3O4 nanoparticles to water increases the mass transfer coefficient (MTC), and that it increases with an increase in nanofluid concentration. For a concentration of 0.05 vol% nanofluid, the MTC was improved 111% and 13.7% in the turbulent and laminar flow regimes, respectively. The mass transfer coefficient of CO2 in water and effective mass transfer coefficient in nanofluid were increased up to 10% and 29% in the presence of a parallel alternative magnetic field, respectively.

Experimental determination of thermophysical properties of Indonesian fly-ash nanofluid for heat transfer applications

The heat transfer fluid's thermal properties are a significant topic of current research. In this study, coal fly ash nanoparticles of 14 nm average diameter were dispersed in water to prepare stable nanofluid in the concentration range of 0.1–0.5% volume concentration. The nanofluid was stabilized and uniformly dispersed using an ultrasonic homogenizer with the addition of Triton–X 100 surfactant. The thermophysical properties, viz., thermal conductivity, viscosity, density, and specific heat of the nanofluid were measured in the temperature range of 30–60 °C. The maximum thermal conductivity and viscosity augmentation of 14 and 6.38% are observed for 60 and 30 °C, respectively, at 0.5% volume concentration compared to water at the same temperatures. The experiment results revealed that thermal conductivity, viscosity, and density increased while specific heat decreased with an increase in nanofluid concentration. Also, the thermal conductivity and specific heat increase, while viscosity and density decrease with an increase in temperature. The thermal conductivity of fly ash nanofluid is observed to be superior by 3.9% compared to SiO2 nanofluid which can be due to its chemical constituents. Hence, fly ash particles are useful in heat transfer applications.

Motion of Nanofluid Droplets through Immiscible Quiescent Liquid: An Experimental Study

Motion of droplets in liquid –liquid extraction column is of importance for many industrial processes. This study aims at evaluation of hydrodynamic behavior of a nanofluid particle moving through an immiscible liquid. Toluene based nanofluids were used as referral systems in this study. Nanoparticles of ZnO, Al2O3, SiO2 and TiO2 have been used to synthesize stable nanofluids. The experiments were carried out using different concentrations of nanoparticles to study the variation in terminal velocity, drag coefficient and eccentricity of the nanofluid droplet. Observations show enhancement in terminal velocity and reduction in drag coefficient of the droplets, for all nanofluids up to optimum concentration of nanoparticles. With increase in concentration of nanofluid beyond the optimum concentration, the droplet terminal velocity decreases and drag coefficient increases due to deformation in shape and an increase in oscillation that could be due to nanoparticle aggregation in nanofluid. The eccentricity of...

Three‐dimensional computational comparison of mini pinned heat sinks using different nanofluids: Part one—the hydraulic‐thermal characteristics

AbstractThe hydraulic‐thermal characteristics of 3D pinned heat sink designs have been numerically compared as the first part of a three‐part investigation. Five different pin geometries (circular, square, triangular, strip, and elliptic pins) and an unpinned heat sink with three types of nanofluids (Al2O3–H2O, SiO2–H2O, and CuO–H2O) are considered for laminar forced convection. The range of Reynolds number is from 100 to 1000, and volume fractions vary between 0% and 5%. The finite volume method is employed to solve the Navier–Stokes and energy equations by employing a SIMPLE algorithm for a computational solution. Three parameters are presented—the Nusselt number, the bottom temperature, and the hydrothermal performance of the heat sink with pressure drop data. The findings indicated that the overall hydrothermal performance of elliptic‐pinned (EP) heat sinks produces the most substantial value of 3.10 for pure water. For different nanofluids, the SiO2–water nanofluids with EPs have the most significant hydrothermal performance. Also, this factor is enhanced with an increase in nanofluid concentration up to nearly 3.34 for 5% of SiO2–water. Consequently, applying the elliptic‐pinned heat sinks is recommended with pure water for considering an increase in the pressure drop, with 5% of SiO2–water nanofluids, regardless of an enlargement of pressure drop for heat‐dissipation applications.

Flow and heat transfer of nanofluid in a channel partially filled with porous media considering turbulence effect in pores

The flow and heat transfer of Al2O3–water nanofluid in a channel partially filled with porous media is investigated numerically. The turbulence effect in the porous media is taken under consideration in this article. A simple case is simulated first to evaluate the accuracy of the results in comparison with the available data. The turbulent kinetic energy profile is investigated at a flow cross section. The results show that the maximum turbulent kinetic energy occurs in the clear fluid region in the vicinity of the porous media region. The turbulent kinetic energy is a decreasing function of the porosity of the porous medium. The effect of porosity on the variation of turbulent kinetic energy decreases with the increase in the porosity of the porous medium. The turbulent kinetic energy in clear fluid and porous media regions decreases with the increase in nanofluid concentration from 0.01 to 0.03, and it increases with the increase in nanofluid concentration from 0.03 to 0.05. The temperature of the nanofluid increases with the increase in the nanofluid concentration and decrease in the porosity of porous media. It is shown that for this case, with the increase in nanofluid concentration and porosity of porous media, the skin friction coefficient increases and the Nusselt number decreases.

Determination of Optimum Concentration of Nanofluid for Process Intensification of Heat Transfer Using Corrugated Plate Type Heat Exchanger

Abstract In this study cooling of hot water is taken up using a compact heat exchanger such as corrugated plate type heat exchanger and with utility fluid as a nanofluid prepared from mixing Al2O3 in water. In general a monotonic increase of 30 % to 70 % in overall heat transfer coefficient is observed for increase in nanofluid concentration as well as its flow rate. An optimum concentration of nanofluid is hence not possible to be found as heat transfer coefficient exhibited a monotonic trend. But there is a penalty for using nanofluid of higher concentrations in heat exchangers in the form of additional hydraulic power required to supply the nanofluid due its higher viscosity. Hence, as a novel approach, a target temperature drop of 15 °C for hot fluid (with constant flow rate) is assumed and the minimum critical flow rate of cold nanofluid of various concentrations required for achieving this is determined using simulation. For such a critical flow rate at various nanofluid concentrations, the determined hydraulic power (product of pressure drop and flow rate) exhibited a global minimum around 0.75 % volume concentration of Al2O3 in water. Thus this article presents the process intensification procedure for the heat exchangers using nanofluids as heat transfer enhancement option.

X-ray imaging analysis on behaviors of boiling bubbles in nanofluids

Nanofluid, a liquid suspension containing nanoparticles, has been widely used to enhance heat transfer. However, the heat transfer enhancement mechanism of nanofluids has not been clearly revealed yet. Therefore, understanding the boiling heat transfer of nanofluids is a challenging research issue in the field of heat transfer. When nanoparticles are added into a base fluid, the thermo-physical properties of the fluid and surface characteristics are modified. Those modifications induce changes in the behavior of boiling bubbles. In addition to the size and number of bubbles, the generating rate of boiling bubbles was newly defined to estimate the heat transfer coefficient directly from bubble behaviors according to nanofluid concentration. As the nanofluid concentration increases, both the generating rate of boiling bubbles and the heat transfer coefficient decrease. Wettability and hydrodynamic size were also employed to reason those degradations. Wettability increase leads to the reduction of activated nucleation sites, which reduces the bubble generating rate and heat transfer coefficient with an increase in nanofluid concentration. In this study, the feasibility and usefulness of synchrotron X-ray imaging and a newly defined boiling generating rate for examining boiling heat transfer were verified by observing boiling-bubble behaviors. Moreover, it was also shown that wettability plays an important role in changes of the bubble behaviors and the heat transfer coefficient as surface roughness modification.

Effect on TEG performance for waste heat recovery of automobiles using MgO and ZnO nanofluid coolants

Present study deals with the theoretical analysis for the performance comparison of automotive waste heat recovery system with EG-W, ZnO and MgO nanofluidas coolants for TEG system. Effects on performance parameters i.e power output, conversion efficiency and circuit voltage of TEG system with exhaust inlet temperature, total area of TEG, Reynolds number and particle concentration of nanofluids for TEG system have been investigated. Theoretical performance analysis revealed enhancement in output power, conversion efficiency and voltage of the TEG system for MgO nanofluid, followed by ZnO and EG-W coolants. The power output and the conversion efficiency using 1% vol. fraction MgO nanofluid at an inlet exhaust temperature of 500 K, were enhanced by 11.38% and 10.95% respectively, as compared to EG-W coolants. The further increase in nanofluid concentration exhibited a progressive effect on output performance of the TEG system. Further analysis shows that there exists an optimal total area of TEGs for maximum output performance of the system. With MgO nanofluid as a coolant, total area of TEGs can be reduced by up to 33% as compared to EG-W, which would bring significant convenience for the arrangement of TEGs and reduce the cost of TEG system.

Evaporative Characteristics of Al2O3 Nanofluid Droplet on Heated Surface

The present study experimentally investigates the evaporative characteristics for a nanofluid droplet on heated surface. For experiments, the alumina (Al2O3) nanoparticles having a 50 nm average diameter were distributed in deionized (DI)water. The equilibrium contact angles (ECA) of DI-water on bare (without texturing) and hole-patterned textured (by µ-CNC machine) copper surfaces were 60o and 82o. Also, advancing and receding contact angles were 73.3o and 25.8o for bare surface, and 101.3o and 55.2o for textured surface. Surface temperature was fixed as 100±0.2oC, measured by resistance temperature detector (RTD) sensors with data logger. During the experiments, the ambient temperature was 22oC with the relative humidity of 32%. At the initial stage, the dynamic contact angle (DCA) of 0.01 vol.% nanofluid droplet on the textured surface drastically increased over its own ECA due to the generation of large bubbles inside the droplet. However, the contact angle of 0.1vol.% nanofluid droplet at t = 5 s was smaller than that of 0.01vol.% case because the increase in nanofluid concentration caused the reduction of surface tension. After that, DCA gradually decreased until dried out, and total evaporation time was significantly delayed in the case of textured surface. Moreover,the heat transfer characteristics during evaporation phenomenon was affected by the nanofluid concentration and the contact area with the heated surface.

Experimental Investigation of TiO2/Water Nanofluid Droplet Impingement on Nanostructured Surfaces

This paper presents the results of an experimental investigation of nanofluid droplets impacting on nanostructured surfaces. Nanofluids with required weight concentration of 0.25–0.75 wt % were prepared by dispersing TiO2 (21 nm) nanoparticles and appropriate amounts of sodium dodecyl sulfate (SDS) surfactant in Milli-Q water. Superhydrophobic and superhydrophilic coatings were applied over a silicon substrate. The images obtained from the high-speed camera clearly show that when a nanofluid droplet impacts a superhydrophobic surface at room temperature, it spreads, retracts, oscillates, and continues to retract to approximately its initial size. In addition, the increase in nanofluid concentration leads to a decrease in the maximum spreading and the height of droplets after impingement. Also, the use of nanofluids increases the temperature difference at the center of the droplet impact region. TiO2 nanoparticles improve the cooling effectiveness of the droplets on uncoated and superhydrophobic surface up...

Heat transfer intensification in a shell and helical coil heat exchanger using water-based nanofluids

Nanofluids have been reported to be capable of heat transfer intensification. Performance of an agitated shell and helical coil heat exchanger has been experimentally investigated using three water based nanofluids (Al2O3, CuO and TiO2). The studies were carried out at different concentrations of nanofluid, nanofluid temperatures, stirrer speeds and coil-side fluid flow rates. Nanofluids of three concentrations 0.3, 0.6, 1, 1.5 and 2% by weight have been prepared for this purpose. Cetyltrimethyl ammonium bromide (CTAB) was used as stabilizer. Nanofluid was used as heating medium (shell-side) and water was used as coil-side fluid. It was found that heat transfer rate increases with increase in nanofluid concentration. Higher values of nanofluid concentration, stirrer speed and shell-side fluid temperature resulted in greater effectiveness of heat exchanger. A maximum increase of 30.37%, 32.7% and 26.8% in effectiveness of heat exchanger was observed for Al2O3, CuO and TiO2/water nanofluids respectively, when compared to water, indicating intensification of heat transfer.

Thermal Lens Study of Concentration Dependent Thermal Diffusivity of Silver Nanofluid Prepared By Green Synthesis

In this work, silver nanoparticles have been successfully synthesised with a simple, cost effective and reproducible green synthesis method. Honey was chosen as the eco-friendly reducing and stabilizing agent replacing most reported reducing agents like highly reactive chemicals, cause a biological risk to the society and environment. The nanoparticles have been characterized by UV-Vis absorption spectrum exhibits an intense absorption peak around 423 nm and TEM image shows the spherical silver nanoparticles having an average particle size of ~14nm. Thermal diffusivity of silver nanofluid was measured using dual beam thermal lens set up. The thermal diffusivity increases with an increase in nanofluid concentration.